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the gene for the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase is located close to the gene for the large subunit in the cyanobacterium anacystis nidulans 6301.the gene for the small subunit (ss) of ribulose-1,5-bisphosphate carboxylase/oxygenase from a cyanobacterium, anacystis nidulans 6301, has been cloned and subjected to sequence analysis. the ss coding region is located close to and downstream from the large subunit (ls) coding region on the same dna strand. the spacer region between the ls and the ss coding regions contains 93 base pairs (bp), and has no promoter-like sequences. the coding region of a. nidulans ss gene contains 333 bp (111 codon ...19836415615
the cyanobacteriales: a legitimate order based on the type strain cyanobacterium stanieri?as a logical consequence of the definition of a bacterium (stanier and van niel, 1962), r. y. stanier created the name "cyanobacteria" as a replacement for "blue-green algae". as such, cyanobacteria entered the 8th issue of bergey's manual of determinative bacteriology 1974 as members of the procaryotae murray 1968, this kingdom being composed of two divisions, cyanobacteria and bacteria. an even tighter integration of cyanobacteria with other bacteria was proposed by gibbons and murray (1978) f ...19836416126
lipopolysaccharides of the cyanobacterium microcystis aeruginosa.lipopolysaccharides (lps) of two isolates of microcystis aeruginosa were extracted with phenol/water and purified. cesium chloride gradient ultracentrifugation of these preparations yielded only one fraction. the lps contained significant amounts of 3-deoxy-d-manno-octulosonic acid, glucose, 3-deoxy sugars, glucosamine, fatty acids, fatty acid esters, hexoses, and phosphate. heptose, a characteristic sugar component of the polysaccharide moiety of lps of most gram-negative bacteria was absent. l ...19836418544
proton pump coupled to cytochrome c oxidase in the cyanobacterium anacystis nidulans.intact spheroplasts of the cyanobacterium anacystis nidulans were found to oxidize various exogenous c-type cytochromes with concomitant proton extrusion. in the coupled state, h+/e stoichiometries close to 1 were measured, regardless of absolute reaction rates. it is concluded that the proton translocation observed is an intrinsic property of the cytoplasmic membrane-bound cytochrome c oxidase of a. nidulans.19836294060
characterization of reconstituted atpase complex proteoliposomes prepared from the thermophilic cyanobacterium synechococcus 6716.the preparation and some properties are described of proteoliposomes consisting of the atpase complex and lipids from the thermophilic cyanobacterium synechococcus 6716. in the proteoliposomes (about 200 nm in diameter) only a low amount of protein can be incorporated (protein/lipid ratio of 0.01 w/w) and they show very few protein particles on freeze-fracture replicas. the octyl glucoside and cholate dialysis method of reconstitution yielded stable proteoliposomes with a relatively low proton p ...19836197302
isolation, purification and characterization of the atpase complex from the thermophilic cyanobacterium synechococcus 6716.the atpase complex is isolated and purified from membrane vesicles of the thermophilic cyanobacterium synechococcus 6716 by octyl glucoside and cholic acid by a modification of the procedure for its extraction from spinach chloroplasts. the complex is purified by differential centrifugation and ammonium sulfate precipitation and by gel filtration on sepharose 6b. the purified fraction, without any phycocyanin contamination, shows atp hydrolysis activity and pi/atp exchange activity of 1564 and 3 ...19836197306
regulation of the aromatic pathway in the cyanobacterium synechococcus sp. strain pcc6301 (anacystis nidulans).a pattern of allosteric control for aromatic biosynthesis in cyanobacteria relies upon early-pathway regulation as the major control point for the entire branched pathway. in synechococcus sp. strain pcc6301 (anacystis nidulans), two enzymes which form precursors for l-phenylalanine biosynthesis are subject to control by feedback inhibition. 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (first pathway enzyme) is feedback inhibited by l-tyrosine, whereas prephenate dehydratase (enzyme step ...19836129240
evidence for ammonia as an inhibitor of heterocyst and nitrogenase formation in the cyanobacterium anabaena cycadeae.growth and regulation of heterocyst and nitrogenase by fixed nitrogen sources were studied comparatively in parent and glutamine auxotrophic mutant of anabaena cycadeae. the parent strain grew well on n2, nh+4 or glutamine while the mutant strain grew on glutamine but not on n2 or nh+4. the total lack of active glutamine synthetase in the mutant strain thus appears to be the reason for its observed lack of growth in n2 or nh+4, which explains why it is a glutamine auxotroph and at the same time ...19836131672
primary structure of the peptidoglycan from the unicellular cyanobacterium synechocystis sp. strain pcc 6714.a peptidoglycan fraction free of non-peptidoglycan components was isolated from the unicellular cyanobacterium synechocystis sp. strain pcc 6714. hydrofluoric acid treatment (48%, 0 degrees c, 48 h) cleaved off from the peptidoglycan non-peptidoglycan glucosamine, mannosamine, and mannose. the purified peptidoglycan consists of n-acetyl muramic acid, n-acetyl glucosamine, l-alanine, d-alanine, d-glutamic acid, and meso-diaminopimelic acid in approximately equimolar amounts. at least partial amid ...19836131881
the role of specific cations in regulation of cyanobacterial glutamine synthetase.purified glutamine synthetase from the cyanobacterium anabaena cylindrica required a divalent cation for activity. maximum biosynthetic activity required mg2+ (25 mm when supplied alone). co2+ and mn2+ each supported up to 20% of this activity; 12 other cations tested were ineffective. at 2.5 - 10 mm mg2+, 0.1 mm co2+ or ethylene glycol-bis-(beta-aminoethyl ether) n,n'-tetraacetic acid (egta) stimulated gs activity to maximum rates; other divalent cations (particularly mn2+) inhibited mg2+-depen ...19836136275
glutamine and glutamate transport by anabaena variabilis.anabaena variabilis, a dinitrogen-fixing cyanobacterium, has high- and low-affinity systems for the transport of glutamine and glutamate. the high-affinity systems have km values of 13.8 and 100 microm and maximal rates of 13.2 and 14.4 nmol x min-1 x mg of chlorophyll a-1 for glutamine and glutamate, respectively. the low-affinity systems have km values of 1.1 and 1.4 mm and maximal rates of 125 and 100 nmol x min-1 x mg of chlorophyll a-1 for glutamine and glutamate, respectively. glutamine wa ...19836137473
changes in symbiotic and associative interrelations in a higher plant-bacterial system during space flight.the miniature cenosis consisting of the water fern azolla with its associated symbiotic nitrogen-fixing cyanobacterium anabaena and the concomitant bacteria was investigated. ecological closure was shown to produce sharp quantitative and qualitative changes in the number and type of concomitant bacteria. changes in the distribution of bacterial types grown on beef-extract broth after space flight were recorded. anabaena azollae underwent the most significant changes under spaceflight conditions. ...198311542458
photosystem i reaction center from the thermophilic cyanobacterium mastigocladus laminosus.photosystem i reaction center was isolated from the cyanobacterium mastigocladus laminosus. it contained four different subunits with molecular masses (as determined by sodium dodecyl sulfate gels) of about 70,000 (subunit i), 16,000 (subunit ii), 11,000 (subunit iii), and 10,000 (subunit iv) daltons. the purified reaction center contained about 100 chlorophyll a molecules per p(700); however, they could be readily depleted down to about 50 chlorophyll a per p(700) without loss in the photochemi ...198316593284
isolation and sequence of the gene for the large subunit of ribulose-1,5-bisphosphate carboxylase from the cyanobacterium anabaena 7120.cloned dna probes containing genes coding for the large subunit of ribulose-1,5-bisphosphate carboxylase (rbca) of corn and of chlamydomonas were used to identify, by heterologous hybridization, dna fragments from anabaena 7120 carrying the corresponding gene sequence. the same probes were used to isolate, from a recombinant lambda library, a 17-kilobase-pair ecori anabaena dna fragment containing the coding sequence for the rbca gene. the entire coding sequence, as well as 210 base pairs of 5' ...198316593300
studies of osmoregulation in salt adaptation of cyanobacteria with esr spin-probe techniques.sucrose is accumulated in response to nacl-induced stress in the cyanobacterium synechococcus 6311. internal cell volume was measured by esr spectra with 2,2,6,6-tetramethyl-4-oxopiperidinoxy free radical (tempone) as a spin probe in order to calculate sucrose concentrations inside the cell. this method is rapid and reliable and provides an unambiguous measurement of absolute volumes in different osmotic environments. because the osmolar concentration of sucrose does not counter-balance the osmo ...198316593309
molecular cloning and sequence analysis of the cyanobacterial gene for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase.ribulose-1,5-bisphosphate carboxylase/oxygenase consists of large subunits (ls) and small subunits. in plants, the ls is encoded in chloroplast dna and the small subunit, in nuclear dna. in cyanobacteria, both subunits are thought to be encoded in chromosomal dna because of prokaryotes. the gene for the ls of ribulose-1,5-bisphosphate carboxylase/oxygenase from a cyanobacterium, anacystis nidulans 6301, has been cloned in pbr322 and subjected to sequence analysis. the coding region contains 1,41 ...198316593333
sequence of the nifd gene coding for the alpha subunit of dinitrogenase from the cyanobacterium anabaena.the nucleotide sequence of nifd, the structural gene for the alpha subunit of dinitrogenase from anabaena 7120, has been determined. the coding sequence contains 1,440 nucleotides, which predict an amino acid sequence of 480 residues and m(r) of 54,283. the predicted sequence contains eight cysteines, of which five are conserved with respect to adjoining sequences and position relative to the alpha subunits of dinitrogenase from azotobacter, clostridium, and klebsiella. because there are also fi ...198316593347
adaptation of the cyanobacterium anabaena variabilis to low co(2) concentration in their environment.the rate of adaptation of high co(2) (5% v/v co(2) in air)-grown anabaena to a low level of co(2) (0.05% v/v in air) was determined as a function of o(2) concentration. exposure of cells to low (2.6%) o(2) concentration resulted in an extended lag in the adaptation to low co(2) concentration. the rate of adaptation following the lag was not affected by the concentration of o(2). the length of the lag period is markedly affected by the o(2)/co(2) concentration ratio, indicating that the signal fo ...198316662790
effects of photosystem ii herbicides on the photosynthetic membranes of the cyanobacterium aphanocapsa 6308.the effects of the photosystem ii herbicides diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea) and atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) on the photosynthetic membranes of a cyanobacterium, aphanocapsa 6308, were compared to the effects on a higher plant, spinacia oleracea. the inhibition of photosystem ii electron transport by these herbicides was investigated by measuring the photoreduction of the dye 2,6-dichlorophenol-indophenol spectrophotometrically using isolated mem ...198316662835
photosynthetic unit organization in a red alga : relationships between light-harvesting pigments and reaction centers.the relative concentration of biliproteins, phycobilisomes, chlorophyll a, and reaction centers i and ii are reported for neoagardhiella bailyei, a macrophytic red alga collected in the field and compared with anacystis nidulans, a cyanobacterium cultured in the laboratory. the ratios of chlorophyll to reaction center i, of chlorophyll to reaction center ii, and the mass of phycobiliprotein per reaction center ii are quite similar in neoagardhiella and anacystis, supporting the concept that the ...198316663016
na-dithionite promotes photosynthetic sulfide utilization by the cyanobacterium oscillatoria limnetica.the light- and sulfide-dependent induction process leading to photosystem i-mediated sulfide utilization by oscillatoria limnetica, for either h(2) evolution or co(2) photoassimilation, was studied. the identical dependence on ph of the lag length, the inhibition of leucine incorporation and final h(2)s concentration imply that the latter exerts a deleterious effect on nonadapted cells.na-dithionite (na(2)s(2)o(4)), na-sulfite (na(2)so(3)), or ethanol cannot serve as photosynthetic electron dono ...198316663093
adaptation of the cyanobacterium microcystis aeruginosa to light intensity.light intensity adaptation (20 to 565 microeinsteins per square meter per second) of microcystis aeruginosa (uv-027) was examined in turbidostat culture. chlorophyll a and phycocyanin concentrations decreased with increasing light intensity while carotenoid, cellular carbon, and nitrogen contents did not vary. variation in the number but not the size of photosynthetic units per cell, based on chlorophyll a/p(700) ratios, occurred on light intensity adaptation. changes in the numbers of photosynt ...198316663094
light-harvesting system of the red alga gracilaria tikvahiae: i. biochemical analyses of pigment mutations.wild type gracilaria tikvahiae, a macrophytic red alga, and fourteen genetically characterized pigment mutants were analyzed for their biliprotein and chlorophyll contents. the same three biliproteins, phycoerythrin, phycocyanin, and allophycocyanin, which are found in the wild type are found in all the mendelian and non-mendelian mutants examined. some mutants overproduce r-phycoerythrin while others possess only traces of phycobiliprotein; however, no phycoerythrin minus mutants were found. tw ...198316663220
ionic osmoregulation during salt adaptation of the cyanobacterium synechococcus 6311.the mechanisms of salt adaptation were studied in the cyanobacterium synechococcus 6311. intracellular volumes and ion concentrations were measured before and after abrupt increases of external nacl concentrations up to 0.6 molar nacl. equilibrium volumes, measured with a rapid and accurate electron spin resonance spin probe method, showed that at low nacl concentrations the cells did not shrink as expected for an impermeable solute. however, when the nacl concentration exceeded a critical value ...198316663223
effects of iron starvation on the ultrastructure of the cyanobacterium agmenellum quadruplicatum.the effects of iron starvation on the ultrastructure of the unicellular cyanobacterium agmenellum quadruplicatum were studied by using thin sectioning and transmission electron microscopy. intracellular polysaccharide began to accumulate at the onset of iron limitation. this was followed by degradation of ribosomes and (later) degradation of the thylakoid membranes, both of which were virtually absent by 200 h. the thylakoids underwent structural modifications and rearrangements before they actu ...198316346226
effects of iron starvation on the physiology of the cyanobacterium agmenellum quadruplicatum.the effects of iron starvation on the growth and physiology of the unicellular cyanobacterium agmenellum quadruplicatum were studied. uptake of iron from the medium did not occur at a constant rate. the majority of the iron was removed at two different times, when the cells were initially inoculated into the medium and after the cultures had become quite dense and had stopped growing. iron became limiting for growth 16 h after transfer to an iron-deficient medium, but cultures retained full viab ...198316346259
role of light intensity and temperature in the regulation of hydrogen photoproduction by the marine cyanobacterium oscillatoria sp. strain miami bg7.the effects of several key environmental factors on the development and control of hydrogen production in the marine blue-green alga (cyanobacterium) oscillatoria sp. strain miami bg7 were studied in relation to the potential application of this strain to a bio-solar energy technology. the production of cellular biomass capable of evolving hydrogen gas was strongly affected by light intensity, temperature, and the input of ammonia as a nutrient. depletion of combined nitrogen from the growth med ...198316346266
direct measurements of steady-state kinetics of cyanobacterial n(2) uptake by membrane-leak mass spectrometry and comparisons between nitrogen fixation and acetylene reduction.a mass spectrometer with a membrane-covered inlet was used to measure nitrogen fixation by following changes in the concentration of dissolved n(2) in a stirred suspension of the cyanobacterium anabaena variabilis in an open system. the results showed a good fit to michaelis-menten kinetics with a k(m) for n(2) of 65 mum at 35 degrees c, corresponding to 0.121 atmosphere of n(2). corresponding values for the k(m) for acetylene reduction were 385 mum (0.011 atmosphere at 35 degrees c). comparison ...198316346272
partitioning of co(2) fixation in the colonial cyanobacterium microcystis aeruginosa: mechanism promoting formation of surface scums.constraints on inorganic carbon (c(i)) availability stimulated buoyancy in natural, photosynthetically active populations of the colonial blue-green alga (cyanobacterium) microcystis aeruginosa. in nonmixed eutrophic river water and cultures, o(2) evolution determinations indicated c(i) limitation of photosynthesis, which was overcome either by co(2) additions to the aqueous phase or by exposure of buoyant colonies to atmospheric co(2). microautoradiographs of m. aeruginosa colonies revealed par ...198316346344
production of spirulina biomass: maintenance of monoalgal culture outdoors.the effects of sodium bicarbonate concentration, population density, and temperature on the maintenance of an outdoor monoculture of the cyanobacterium spirulina platensis were studied. a clear response by spirulina to the concentration of bicarbonate was evident, with 0.2m bicarbonate representing the lowest concentration in which a monoculture could be maintained. when the temperatures fell during the winter period to some 20-25 degrees c below the optimum for spirulina, chlorella sp. graduall ...198318548655
an unusual phycoerythrin from a marine cyanobacterium.phycoerythrin conjugates are reagents for cell sorting and analyses in which the argon-ion laser line at 488 nanometers is used for excitation. many marine synechococcus strains contain phycoerythrins with absorption maxima at approximately 490 and 550 nanometers; these maxima indicate the presence of phycourobilin and phycoerythrobilin prosthetic groups in the protein. phycoerythrins of red algae contain both groups, but those of freshwater and soil cyanobacteria contain only phycoerythrobilin. ...198417783529
sustained photoproduction of ammonia from dinitrogen and water by the nitrogen-fixing cyanobacterium anabaena sp. strain atcc 33047.conditions have been developed that lengthen the time during which photosynthetic dinitrogen fixation by filaments of the cyanobacterium anabaena sp. strain atcc 33047 proceeds freely, whereas the subsequent conversion of ammonia into organic nitrogen remains blocked, with the resulting ammonia released to the outer medium. when l-methionine-dl-sulfoximine was added every 20 h, maximal rates of ammonia production (25 to 30 mumol/mg of chlorophyll per h) were maintained for about 50 h. after this ...198416346577
microelectrode studies of interstitial water chemistry and photosynthetic activity in a hot spring microbial mat.microelectrodes were used to measure oxygen, ph, and oxygenic photosynthetic activity in a hot spring microbial mat (octopus spring, yellowstone national park), where the cyanobacterium synechococcus lividus and the filamentous bacterium chloroflexus aurantiacus are the only known phototrophs. the data showed very high biological activities in the topmost layers of the microbial mat, resulting in extreme values for oxygen and ph. at a 1-mm depth at a 55 degrees c site, oxygen and ph reached 900 ...198416346607
in vitro fatty acid synthesis and complex lipid metabolism in the cyanobacterium anabaena variabilis: i. some characteristics of fatty acid synthesis.in vitro fatty acid synthesis was examined in crude cell extracts, soluble fractions, and 80% (nh(4))(2)so(4) fractions from anabaena variabilis m3. fatty acid synthesis was absolutely dependent upon acyl carrier protein and required nadph and nadh. moreover, fatty acid synthesis and elongation occurred in the cytoplasm of the cell. the major fatty acid products were palmitic acid (16:0) and stearic acid (18:0). of considerable interest, both stearoyl-acyl carrier protein and stearoyl-coenzyme a ...198416663367
salt adaptation of the cyanobacterium synechococcus 6311 growing in a continuous culture (turbidostat).physiological aspects of salt-adaptation in the cyanobacterium synechococcus 6311 growing in a continuous culture (turbidostat) were studied. the process of salt-adaptation was completed within 3 days, as expressed by the specific growth rate of cells grown in the presence of 0.2 and 0.4 molar nacl. an increase in photosynthetic activity during the adaptation period leads to the accumulation of soluble sugars, essential for osmoregulation in the salt-grown cells. cells grown in the presence of 0 ...198416663376
influence of iron deprivation on the membrane composition of anacystis nidulans.cultures of the cyanobacterium anacystis nidulans were grown under iron-deficient conditions and then restored by the addition of iron. membrane proteins from iron-deficient and iron-restored cells were analyzed by lithium dodecyl sulfate-polyacrylamide gradient gel electrophoresis. the incorporation of [(35)s]sulfate into membrane proteins and lactoperoxidase-catalyzed (125)i iodination were used to monitor the rates of polypeptide biosynthesis and surface exposure of membrane proteins, respect ...198416663393
a highly active oxygen-evolving photosystem ii preparation from the cyanobacterium anacystis nidulans.a highly active o(2)-evolving photosystem (ps)-ii fraction has been isolated from the cyanobacterium, anacystis nidulans r2, using an isolation buffer containing high concentrations of sucrose and salts and subsequent solubilization of the thylakoid membranes with the detergent triton x-100. the isolated fraction had very high psii activity (2500 micromoles o(2) per milligram chlorophyll per hour) and was largely depleted of psi activity. fluorescence emission spectra (77 k) and polypeptide anal ...198416663492
in vitro fatty acid synthesis and complex lipid metabolism in the cyanobacterium, anabaena variabilis: ii. acyl transfer and complex lipid formation.in vitro fatty acid transfer to form complex lipids was observed in crude cell extracts of anabaena variabilis using [1-(14)c]palmitoyl-acyl carrier protein, [1-(14)c]stearoyl-acyl carrier protein, and [1-(14)c]oleoyl-acyl carrier protein substrates. the data indicated that there was a rapid transfer of the fatty acids into the complex lipids. the greatest amount of radioactivity was observed in the monogalactosyl diacylglycerol fractions and there appeared to be a preference for the transfer of ...198416663690
growth and photosynthesis of the cyanobacterium synechococcus leopoliensis in hco(3)-limited chemostats.synechococcus leopoliensis was grown in hco(3) (-)-limited chemostats. growth at 50% the maximum rate occurred when the inorganic carbon concentration was 10 to 15 micromolar (or 5.6 to 8.4 nanomolar co(2)). the o(2) to co(2) ratios during growth were as high as 192,000 to 1. at growth rates below 80% the maximum rate, essentially all the supplied inorganic carbon was converted to organic carbon, and the cells were carbon limited. carbon-limited cells used hco(3) (-) rather than co(2) for growth ...198416663735
characterization of the proton-translocating cytochrome c oxidase activity in the plasma membrane of intact anacystis nidulans spheroplasts.intact spheroplasts of the cyanobacterium (blue-green alga) anacystis nidulans oxidized various exogenous c-type cytochromes with concomitant outward proton translocation while exogenous ferricytochrome c was not reduced. the h(+)/e(-) stoichiometry was close to 1 with each of the cytochromes and did not depend on the actual rate of the oxidase reaction. observed proton ejections were abolished by the uncoupler carbonyl cyanide m-chlorophenylhydrazone. cyanide, azide, and carbon monoxide inhibit ...198416663770
nature of the inorganic carbon species actively taken up by the cyanobacterium anabaena variabilis.the nature of the inorganic carbon (c(i)) species actively taken up by cyanobacteria co(2) or hco(3) (-) has been investigated. the kinetics of co(2) uptake, as well as that of hco(3) (-) uptake, indicated the involvement of a saturable process. the apparent affinity of the uptake mechanism for co(2) was higher than that for hco(3) (-). though the calculated v(max) was the same in both cases, the maximum rate of uptake actually observed was higher when hco(3) (-) was supplied. c(i) uptake was fa ...198416663890
mn and co toxicity in chlorophyll biosynthesis.the metal ion-induced inhibition of tetrapyrrole biosynthesis was studied in the cyanobacterium anacystis nidulans. the accumulation of protoporphyrin and mg protoporphyrin due to the effect of co(2+) and mn(2+) treatment, respectively, pointed to two different sites of inhibition.198416593408
nucleotide sequence of a multiple-copy gene for the b protein of photosystem ii of a cyanobacterium.chloroplast photogene 32 codes for the 32-kilodalton triazine herbicide-binding protein at the b site of electron transport in photosystem ii of the photosynthetic apparatus-its product is the b protein and the gene is accordingly designated ps2b here. the cyanobacteria anacystis nidulans r2, fremyella diplosiphon, and nostoc sp. mac each contain several copies of ps2b. the sequence of one copy of ps2b from fremyella, ps2b-1, has been determined. the longest open reading frame would code for a p ...198416578775
iridium anomaly in the upper devonian of the canning basin, western australia.a moderate iridium anomaly, about 20 times the local background, has been found in upper devonian rocks in the canning basin. it occurs at or near the frasnian-famennian boundary, which is known to be associated with a major massextinction event of global extent. the anomaly occurs in an extremely condensed limestone sequence laid down under quiet deepwater conditions. its occurrence suggests a causal link with some form of meteoroid impact. moreover, carbon isotope data indicate that a large re ...198417799936
contrasting modes of photosynthetic enzyme regulation in oxygenic and anoxygenic prokaryotes.enzymes that are regulated by the ferredoxin/thioredoxin system in chloroplasts--fructose-1,6-bis-phosphatase (fbpase), sedoheptulose-1,7-bisphosphatase (sbpase), and phosphoribulokinase (prk)--were partially purified from two different types of photosynthetic prokaryotes (cyanobacteria, purple sulfur bacteria) and tested for a response to thioredoxins. each of the enzymes from the cyanobacterium nostoc muscorum, an oxygenic organism known to contain the ferredoxin/thioredoxin system, was activ ...198411536590
succession in a microbial mat community: a gaian perspective.the gaia hypothesis originally proposed by james e. lovelock states that the composition, oxidation-reduction state and temperature of the troposphere are actively regulated by the activities of the biota. the gaian concept has been extrapolated to include the composition of surface sediments through the process of biomineralization. the stratified microbial community dominated by the cyanobacterium microcoleus chthonoplastes is actively involved in the deposition of laminated sediments at lag ...198411537776
purification and characterization of thioredoxin from the n2-fixing cyanobacterium anabaena cylindrica.thioredoxin has been purified to homogeneity from the cyanobacterium anabaena cylindrica. the protein consists of a single polypeptide chain with a relative molecular mass of about 11 680 which has two cysteine residues (residues 31 and 34) in the sequence-cys-gly-pro-cys- and an isoelectric point at ph 4.55. the n-terminal amino acid sequence of 39 residues shows distinct homologies with the sequences of escherichia coli and corynebacterium nephridii thioredoxins. anti-(a. cylindrica thioredoxi ...19846146520
heterocyst differentiation in cylindrospermum licheniforme: studies on the role of transcription.heterocysts of the cyanobacterium cylindrospermum licheniforme occur at the ends of the filaments. these cells, specialized for aerobic n2 fixation, synchronously differentiate after the fragmentation of filaments grown in a medium free of combined nitrogen. this study has examined the role of transcription during and after heterocyst differentiation. autoradiography of intact filaments pre-labelled for 3 h with [3h]uracil revealed that rna synthesis occurred at similar rates in vegetative cells ...19846204007
a new method for identification of heterocysts and proheterocysts in morphologically complex cyanobacteria.a new light microscopic method for identifying heterocysts and proheterocysts in morphologically complex cyanobacteria was evaluated for reliability and usefulness. mature heterocysts and proheterocysts could be distinguished readily from vegetative cells in 0.25 micron sections of fixed and embedded material after staining with toluidine blue. examination by light and electron microscopy of the same specimens indicated that the staining reactions which served to differentiate these cell types w ...19846207642
purification of a high molecular weight membrane protein by fast protein liquid chromatography: the atpase complex of a thermophilic cyanobacterium.fast protein liquid chromatography (fplc) with a strong anion-exchange (mono q) column is applied to the purification of a high molecular weight membrane protein. the atpase complex of the thermophilic cyanobacterium synechococcus 6716, partially purified by ammonium sulfate precipitation, was fractionated in the presence of the detergent octylglucoside. the atpase complex containing fractions were eluted by a linear nacl gradient at about 0.4 m and within 10 min. the fplc fractions were analyze ...19846234347
lipid specificity for the reconstitution of well-coupled atpase proteoliposomes and a new method for lipid isolation from photosynthetic membranes.the lipid specificity for the enzymatic and proton-translocating functions of a reconstituted thermophilic atpase complex has been investigated. the proteoliposomes were prepared from the atpase complex of the thermophilic cyanobacterium synechococcus 6716 and various lipids and lipid mixtures extracted from this organism and from a related mesophilic strain. some commercial lipids were used as well. an improved method of lipid extraction from chlorophyll-containing membranes is presented. this ...19846237908
cotranscription of genes encoding the small and large subunits of ribulose-1,5-bisphosphate carboxylase in the cyanobacterium anabaena 7120.in the filamentous cyanobacterium anabaena, the gene for the small subunit (rbcs) of ribulose-1,5-bisphosphate carboxylase is linked to and transcribed together with the gene encoding the large subunit (rbcl) of the same enzyme. the two genes are separated by a spacer of 545 base pairs (bp) that does not contain an open reading frame. both genes hybridize with a predominant 3.1-kilobase transcript that initiates 414 bp upstream from the rbcl coding region. the nucleotide sequence 14-8 bp precedi ...19846091125
the role of na2s in anoxygenic photosynthesis and h2 production in the cyanobacterium nostoc muscorum.na2s is known to support anoxygenic photosynthesis in some strains of cyanobacteria and to stimulate h2 production in n2 fixing filaments of nostoc muscorum. we have shown electron transfer between na2s and photosystem i to be dependent on cytochrome b559 which was detected only in vegetative cells. an electron mediator was required to support na2s driven nitrogenase activity in isolated heterocysts. na2s was also found to deplete the atp pool, probably by inhibiting electron transfer from photo ...19846091649
proton movements and electric potential generation in reconstituted atpase proteoliposomes from the thermophilic cyanobacterium synechococcus 6716.atp hydrolysis-induced proton translocation and electric potential generation have been studied in atpase proteoliposomes by means of various optical probes. the proteoliposomes consisted of reconstituted atpase complex and native lipid mixture isolated from the thermophilic cyanobacterium synechococcus 6716 [van walraven et al. (1983) eur. j. biochem. 137, 101-106]. the native cartenoids and added oxonol vi served as probes for the electric membrane potential generated by the net charge separat ...19846092075
triton x-114 phase fractionation of membrane proteins of the cyanobacterium anacystis nidulans r2.the thylakoid polypeptides of the cyanobacterium anacystis nidulans r2 were analyzed by triton x-114 phase fractionation [c. bordier (1981) j. biol. chem. 256, 1604-1607, as adapted for photosynthetic membranes by t.m. bricker and l.a. sherman (1982) febs lett. 149, 197-202]. in this procedure, polypeptides with extensive hydrophobic regions (i.e., intrinsic proteins) form mixed micelles with triton x-114, and are separated from extrinsic proteins by temperature-mediated precipitation of the mix ...19846093709
isolation and characterization of thioredoxin f from the filamentous cyanobacterium, anabaena sp. 7119.two thioredoxin fractions had previously been reported to occur in anabaena 7119 by buchanan and co-workers (yee, b. c., dela torre, a., crawford, n. a., lara, c., carlson, d. e., and buchanan, b. b. (1981) arch. microbiol. 130, 14-18). these proteins were detected by their ability to activate spinach fructose-1,6-bisphosphatase (fru-p2-ase). the partially purified proteins resembled similar thioredoxins found in spinach chloroplasts and were designated thioredoxin f (tf) for the fraction most e ...19846094540
chloroplast promoter driven expression of the chloramphenicol acetyl transferase gene in a cyanobacterium.the putative promoter region of the chloroplast encoded ps2b gene (the gene encoding the 32kd herbicide binding b protein of photosystem ii (1-4)) has been fused to a chloramphenicol acetyl transferase (cat) gene that lacks its bacterial promoter and found to accurately initiate transcription from this promoter when introduced into the cyanobacterium, anacystis nidulans r2 (or into e. coli). the chloroplast promoter-cat fusion was introduced into the cells on a plasmid that contains plasmid repl ...19846096812
cloning of a third nitrate reductase gene from the cyanobacterium anacystis nidulans r2 using a shuttle cosmid library.a strategy for gene cloning in the cyanobacterium anacystis nidulans r2 was developed which made use of a gene library constructed in a shuttle cosmid vector. the method involved phenotypic complementation of mutants with pooled cosmid dna. the development of the procedure and its application to the cloning of a third gene involved in nitrate reduction are described.19846098517
heterocyst differentiation in the cyanobacterium mastigocladus laminosus.the morphological and ultrastructural aspects of heterocyst differentiation in the branching, filamentous cyanobacterium mastigocladus laminosus were examined with light and electron microscopy. the earliest differentiation stages involved cytoplasmic changes, including (i) rapid degradation of carboxysomes, (ii) degradation of polysaccharide granules, and (iii) accumulation of electron-dense ribosomal or protein material (or both). intermediate differentiation stages involved synthesis of a hom ...19846420391
interaction of constituent subunits in ribulose 1,5-bisphosphate carboxylase from aphanothece halophytica.ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) from the halophilic cyanobacterium, aphanothece halophytica, dissociates into catalytic core (large subunit a oligomer) and small subunit b under low ionic strength during sucrose density gradient centrifugation. supplementation of kcl, nacl, or k2so4 ( [i] = 0.3 m) partly prevents the dissociation, the preventive effect of divalent cation salts such as mgcl2 and cacl2 being more effective than monovalent cation salts. rubisco with its hi ...19846422849
the effect of suspended particulate material on cyanobacteria--cyanophage interactions in liquid culture.the effect of the lytic phage lpp-dun1 on the cyanobacterium plectonema boryanum has been investigated in batch and in continuous cultures in the presence and absence of silt. in batch culture plectonema without added phage grew normally; the presence of phage caused rapid lysis of the cyanobacterium and the addition of silt prevented lysis by the phage. in continuous culture the numbers of cyanobacterial cells and phage particles oscillated in a reciprocal manner, but the addition of silt dampe ...19846423604
purification and properties of glutathione reductase from the cyanobacterium anabaena sp. strain 7119.an nadph-glutathione reductase (ec 1.6.4.2) has been purified 6,000-fold to electrophoretic homogeneity from the filamentous cyanobacterium anabaena sp. strain 7119. the purified enzyme exhibits a specific activity of 249 u/mg and is characterized by being a dimeric flavin adenine dinucleotide-containing protein with a ratio of absorbance at 280 nm to absorbance at 462 nm of 5.8, a native molecular weight of 104,000, a stokes radius of 4.13 nm, and a pi of 4.02. the enzyme activity is inhibited ...19846425264
optimal conditions for genetic transformation of the cyanobacterium anacystis nidulans r2.under optimal conditions, the cyanobacterium anacystis nidulans r2 was transformed to ampicillin resistance at frequencies of greater than 10(7) transformants per microgram of plasmid (pch1) donor dna. no stringent period of competency was detected, and high frequencies of transformation were achieved with cultures at various growth stages. transformation increased with time after addition of donor dna up to 15 to 18 h. the peak of transformation efficiency (transformants/donor molecule) occurre ...19846425267
instability and variable toxicity of hbp-tx, a toxin in the cyanobacterium microcystis aeruginosa.it was found that autoxidative degradation is responsible for the inactivation of the unstable microcystis toxin hbp-tx. the purified toxin was similar in its properties to the "fast-death-factor" in microcystis, described as a cyclic peptide in the literature. the apparent presence of an entirely different toxin was simulated by the partially inactivated hbp-tx. a number of associated fluorescent compounds were identified as the non-toxic degradation products of the toxin. as a consequence, as ...19846426092
length of foreign dna in chimeric plasmids determines the efficiency of its integration into the chromosome of the cyanobacterium synechococcus r2.the photosynthetic cyanobacterium synechococcus r2 is efficiently transformed by dna molecules that contain antibiotic genes from escherichia coli linked to a segment of synechococcus r2 chromosomal dna. antibiotic-resistant transformants result from integration of donor dna into the cyanobacterial chromosome by homologous recombination. foreign dna interrupting the cyanobacterial sequence in the donor molecule integrates by replacement of homologous recipient dna with donor dna containing the f ...19846428977
na+ requirement for growth, photosynthesis, and ph regulation in the alkalotolerant cyanobacterium synechococcus leopoliensis.we have found that na+ is required for the alkalotolerance of the cyanobacterium synechococcus leopoliensis. cell division did not occur at any ph in the absence of na+, but cells inoculated into na+-free growth medium at ph 6.8 did continue metabolic activity, and over a period of 48 h, the cells became twice their normal size. many of these cells remained viable for at least 59 h and formed colonies on na+ -containing medium. cells grown in the presence of na+ and inoculated into na+ -free gro ...19846429118
effects of pesticides on cyanobacterium plectonema boryanum and cyanophage lpp-1.cyanobacterium plectonema boryanum iu 594 and cyanophage lpp-1 were used as indicator organisms in a bioassay of 16 pesticides. experiments such as spot tests, disk assays, growth curves, and one-step growth experiments were used to examine the effects of pesticides on the host and virus. also, experiments were done in which host or virus was incubated in pesticide solutions and then assayed for pfu. p. boryanum was inhibited by four herbicides: 3-(3,4-dichlorophenyl)-1,1-dimethylurea (dcmu), 1, ...19846430230
na+/h+ exchange in the cyanobacterium synechococcus 6311.the cyanobacterium synechococcus 6311 adapts to grow in 0.6 m nacl by developing an efficient system for sodium extrusion. in the present investigation cells loaded with nac1 were subjected to a large dilution. changes in fluorescence quenching of acridine orange as a function of transmembrane na+ gradients provide evidence that na+/h+ exchange activity greatly enhanced in salt-adapted cells.19846430295
vanadate and dicyclohexylcarbodiimide insensitive proton extrusion from oxygen pulsed cells of the cyanobacterium anacystis nidulans.oxygen pulses applied to dark anaerobic suspensions of anacystis nidulans provoked immediate acidification of the external medium. the reaction was inhibited only 75% by dicyclohexylcarbodiimide and 7-chloro-4-nitrobenz-2-oxa-1,3-diazole at concentrations which completely arrested all oxidative phosphorylation. carbonyl cyanide m-chlorophenylhydrazone eliminated the acidification of oxygen pulsed cell suspensions while ortho-vanadate and diethylstilbestrol had no effect. no lag occurred between ...19846433918
catalytically active hybrids formed in vitro between large and small subunits of different procaryotic ribulose bisphosphate carboxylases.ribulose bisphosphate carboxylase from the procaryotic green alga, prochloron (the symbiont of lissoclinum patellum), has eight large and eight small subunits, and a low affinity for co2, similar to that of cyanobacterial carboxylases. the small subunits were progressively removed from this carboxylase and from that from the cyanobacterium, synechococcus acmm 323, by twice-repeated, mild-acid precipitation. this procedure produced large-subunit octamers, greatly depleted in small subunits, as we ...19846435536
regulation of the nitrate reductase level in anacystis nidulans: activity decay under nitrogen stress.the in vivo stability of ferredoxin-nitrate reductase from the cyanobacterium anacystis nidulans under conditions of inhibited protein synthesis has been studied in nitrate-grown cells. a light-promoted rapid decay in cellular nitrate reductase activity took place in the absence of any added nitrogen source, but not in the presence of nitrate, nitrite, or ammonium. the inactivation process seemed to proceed in two sequential steps. the first step required both light and oxygen, and was inhibited ...19846437330
cloning and sequencing of the genes encoding the alpha and beta subunits of c-phycocyanin from the cyanobacterium agmenellum quadruplicatum.synthetic oligonucleotide probes were used to identify a cloned dna fragment from the cyanobacterium agmenellum quadruplicatum that contains the genes for the alpha and beta subunits of c-phycocyanin. the coding region for the alpha-subunit gene begins 108 base pairs downstream from the 3' end of the beta-subunit structural gene. the sequences of the coding regions for both genes have been determined as well as 379 base pairs of 5' flanking region, 204 base pairs of 3' flanking region, and the 1 ...19846438628
phylogeny of the 5s ribosomal rna from synechococcus lividus ii: the cyanobacterial/chloroplast 5s rnas form a common structural class.the complete nucleotide sequence of the 5s ribosomal rna from the cyanobacterium synechococcus lividus ii has been determined. the sequence is (sequence in text) this 5s rna has the cyanobacterial- and chloroplast-specific nucleotide insertion between positions 30 and 31 (using the numbering system of the generalized eubacterial 5s rna) and the chloroplast-specific nucleotide-deletion signature between positions 34 and 39. the 5s rna of s. lividus ii has 27 base differences compared with the 5s ...19846443313
complete nucleotide sequence of the 23s rrna gene of the cyanobacterium, anacystis nidulans.the nucleotide sequence of the anacystis nidulans 23s rrna gene, including the 5'- and 3'-flanking regions has been determined. the gene is 2876 nucleotides long and shows higher primary sequence homology to the 23s rrnas of plastids (84.5%) than to that of e. coli (79%). the predicted rrna transcript also shares many secondary structural features with those of plastids, reinforcing the endosymbiont hypothesis for the origin of these organelles.19846326060
cloning of nitrate reductase genes from the cyanobacterium anacystis nidulans.anacystis nidulans, a non-nitrogen-fixing cyanobacterium, can fulfill its nitrogen requirement by the assimilation of nitrate. the first step in the pathway, the reduction of nitrate to nitrite, is catalyzed by the molybdo-protein nitrate reductase. in this study, newly developed techniques for gene cloning in a. nidulans r2 were used for the isolation of two genes involved in nitrate reduction. one gene was cloned by complementation of the corresponding mutant; the other gene was picked up from ...19846330039
two tuf genes in the cyanobacterium spirulina platensis.probes derived from the tufa gene of escherichia coli have been utilized to detect homologous sequences on spirulina platensis dna. a 6-kilobase-pair fragment of s. platensis dna appears to contain two sequences homologous to the e. coli gene. thus, as reported for gram-negative bacteria, the cyanobacterium presumably contains two tuf genes.19846330044
validity of the tritiated thymidine method for estimating bacterial growth rates: measurement of isotope dilution during dna synthesis.the rate of tritiated thymidine incorporation into dna was used to estimate bacterial growth rates in aquatic environments. to be accurate, the calculation of growth rates has to include a factor for the dilution of isotope before incorporation. the validity of an isotope dilution analysis to determine this factor was verified in experiments reported here with cultures of a marine bacterium growing in a chemostat. growth rates calculated from data on chemostat dilution rates and cell density agr ...19846517579
the use of carotenoids and oxonol vi as probes for membrane potential in proteoliposomes.carotenoids present in lipids extracted from the cyanobacterium synechococcus 6716 indicate trans-membrane potential in proteoliposomes reconstituted from these lipids and the atpase complex isolated from the same organism. a carotenoid absorbance band shift to a longer wavelength is obtained with valinomycin-induced potassium ion diffusion potentials, irrespective of the polarity of the potassium gradient. in contrast to this, the (externally added) probe oxonol vi only shows an absorbance band ...19853157600
use of streptavidin to detect biotin-containing proteins in plants.a procedure to detect biotinyl proteins after fractionation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was developed. proteins were immobilized on nitrocellulose and biotin-containing proteins were detected by probing with 125i-streptavidin. using this procedure a small survey of biotinyl protein in plants was undertaken. in total four biotin-containing proteins were detected in higher plants of molecular weights 62,000, 50,000, 34,000, and 31,000. these biotinyl proteins were ...19852866733
characterization of a cyanobacterial photosystem i complex.a simple procedure is described for the preparation of photosystem i (psi) particles from triton x-100-solubilized thylakoid membranes of the unicellular cyanobacterium synechococcus 6301. the purified psi complex contained the full complement of antenna chlorophylls, 130 +/- 5/p700, displayed the electron paramagnetic resonance signals characteristic of iron-sulfur centers x, a, and b, and had a protein/chlorophyll ratio of 2.9. determination of the polypeptide composition, utilizing a uniforml ...19852981224
three restriction endonucleases from anabaena flos-aquae.three site-specific endonucleases, afli, aflii and afliii, have been partially purified from the cyanobacterium anabaena flos-aquae ccap 1403/13f. their recognition and cleavage specificities have been determined to be: (formula; see text) aflii and afliii are new specificities and may be useful in molecular cloning, as well as in the analysis of dna. the distribution of type ii restriction endonucleases in the cyanobacteria is briefly discussed.19852985742
epr signals of redox active copper in edta washed membranes of the cyanobacterium synechococcus 6311.a signal of cu2+ (g = 2.03) was detected by electron paramagmetic resonance spectroscopy in oxidized membrane preparations of synechococcus 6311. the membranes were prepared and washed in the presence of edta (10mm, ph 8.0) and, hence, were depleted of adventitious copper; the treatment also would remove any membrane-associated soluble redox proteins and other paramagnetic metal ions. 0.1% triton x-100 facilitated detection of the cu2+ signal which was fully reduced by dithionite or ascorbate pl ...19852988542
cloning of phosphoenolpyruvate carboxylase gene from a cyanobacterium, anacystis nidulans, in escherichia coli.the phosphoenolpyruvate carboxylase gene (ppc) from anacystis nidulans, a cyanobacterium (blue-green alga), was cloned in escherichia coli. chromosomal dna of a. nidulans was partially digested with sau3ai, and the obtained dna fragments were ligated in the bamhi site of pbr322. the hybrid plasmids were first transformed into e. coli k802 (hsdr-, hsdm+) to obtain the gene bank of a. nidulans. the bank consisted of about 12,000 clones. these hybrid plasmids were then transformed into e. coli pcr1 ...19852989256
a new endonuclease recognizing the deoxynucleotide sequence ccnngg from the cyanobacterium synechocystis 6701.a new sequence-specific endonuclease from the cyanobacterium synechocystis species pcc 6701 has been purified and characterized. this enzyme, seci, is unique in recognizing the nucleotide sequence: 5' -ccnngg-3' 3' -ggnncc-5' and cleaves it at the position indicated by the symbol. two other restriction endonucleases, secii and seciii, found in this organism are isoschizomers of mspi and mstii, respectively.19852997722
molecular cloning and nucleotide sequence of a developmentally regulated gene from the cyanobacterium calothrix pcc 7601: a gas vesicle protein gene.since the gas vesicle protein (gvp) is highly conserved among the different gas-vacuolate prokaryotes, a 29-mer oligonucleotide corresponding to a portion of the anabaena flos-aquae gvp gene was synthesized and used to isolate the gvp structural gene from calothrix pcc 7601 (= fremyella diplosiphon). gas vacuole production in this filamentous cyanobacterium is restricted to hormogonia which occur at a specific stage during the developmental cell cycle. the gvp gene (gvpa) was localized on a 709 ...19852997744
expression of the escherichia coli lacz gene on a plasmid vector in a cyanobacterium.a biphasic plasmid vector was used to introduce the escherichia coli k-12 lac operon into the unicellular cyanobacterium agmenellum quadruplicatum pr-6. the pr-6 transformants expressed beta-galactosidase at nearly as high a level as did escherichia coli transformants. in order to accomplish this, it was necessary to obtain pr-6 mutants that could be transformed by plasmids with unmodified recognition sites for the endogenous pr-6 restriction endonuclease aqu i. these mutants were generated by a ...19852997920
nucleotide sequence of the phosphoenolpyruvate carboxylase gene of the cyanobacterium anacystis nidulans.nucleotide sequence of the open reading frame (orf) for the phosphoenolpyruvate carboxylase gene (ppc) of the cyanobacterium anacystis nidulans was determined. the orf consists of 3159 bp and codes for 1053 amino acid (aa) residues. the codon usage of the ppc of a. nidulans is not so markedly different from that of the escherichia coli ppc, yet, in a. nidulans the preferred codons are aag for lysine and ccc for proline, whereas those are seldom used in the e. coli ppc.19852998946
self-cloning in the cyanobacterium anacystis nidulans r2: fate of a cloned gene after reintroduction.functional analysis of cloned genes often makes use of complementation after introducing these genes into cells of a mutant strain. problems with this self-cloning step in the cyanobacterium anacystis nidulans r2 have been encountered, which were mainly due to recombinational instability of gene and vector after transformation. therefore, conditions determining the exchange of material between chromosome, insert and plasmids were studied to achieve the necessary stability. the fate of plasmid pm ...19853006100
[recombinant plasmids capable of integration into the chromosome of the cyanobacterium anacystis nidulans r2].recombinant plasmids, series piab and piah, have been constructed by insertion of bamhi or hindiii chromosomal fragments from anacystis nidulans r2 into the tet gene of plasmid pacyc184. plasmids piab and piah are stably maintained in escherichia coli cells and transfer the cmr marker in transformation of anacystis nidulans. blot hybridization technique has shown the formation of cmr clones in transformation to result from integration of plasmid pacyc184 with the chromosome of cyanobacterium.19853025685
[plasmids of the cyanobacterium synechocystis sp. 6803].three cryptic plasmids have been isolated from cyanobacterium synechocystis sp. 6803::pss2 (1.4 md), pss3 (36 md), pss4 (60 md). plasmid dna was isolated in cs-cl-eb density gradient and analyzed by gel electrophoresis and electron microscopy by gel electrophoresis and electron microscopy techniques. the restriction map is constructed for plasmid pss2 having the cleavage sites for sau3a, hincii, hindiii, mspi restriction endonucleases. the plasmid may be used to construct the recombinant vector ...19853025718
effect of heat shock on protein synthesis in the cyanobacterium synechococcus sp. strain pcc 6301.the response to heat shock at 47 degrees c was examined in the cyanobacterium (blue-green alga) synechococcus sp. strain pcc 6301. on heat shock, the growth of the cells decreased and they preferentially synthesized a limited number of polypeptides. the rate of synthesis of these proteins increased markedly in the early period of temperature shift up and gradually decreased afterwards. among the proteins greatly affected by temperature shift up were those with apparent molecular weights of 91,00 ...19853918983
effect of nitrogen starvation on the morphology and ultrastructure of the cyanobacterium mastigocladus laminosus.the effects of nitrogen starvation on the morphology and ultrastructure of the branching, filamentous cyanobacterium mastigocladus laminosus were examined with light and electron microscopy. the internal ultrastructural characteristics of vegetative cells changed markedly during nitrogen starvation. carboxysomes were degraded, while polyphosphate bodies and lipid bodies accumulated. the ultrastructure of mature heterocysts was also affected by nitrogen starvation; their intracytoplasmic membrane ...19853918986
factors affecting the dissociation and reconstitution of ribulose-1,5-bisphosphate carboxylase/oxygenase from aphanothece halophytica.factors affecting the mutual interaction between the catalytic core [octamer of large subunit (a)] and the small subunit (b) comprising ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) from the superhalophilic cyanobacterium, aphanothece halophytica, were investigated. the enzyme molecule dissociated into the catalytic core highly depleted of subunit b and the monomeric form of subunit b during density gradient centrifugation (15 h, 4 degrees c) in a sucrose solution of low ionic streng ...19853919647
rearrangement of nitrogen fixation genes during heterocyst differentiation in the cyanobacterium anabaena.nitrogen fixation by the cyanobacterium anabaena is carried out in heterocysts, specialized, non-dividing cells which differentiate under conditions of ammonia or nitrate deprivation. in anabaena, heterocyst differentiation is accompanied by rearrangement of some nitrogen fixation genes. a site-specific recombination between an 11 base-pair direct repeat sequence flanking the nifk and nifd genes removes 11 kilobases of intervening dna, resulting in juxtaposition of the two genes and an alteratio ...19853920531
guidance of cytophaga sp. strain u67 gliding on the sheaths of oscillatoria princeps.individual cells of cytophaga sp. strain u67 glided in helical patterns on the surface of sheaths deposited by the cyanobacterium oscillatoria princeps. possible bases for the helical substructure of the sheath are discussed.19853921528
catalytic properties of a hybrid between cyanobacterial large subunits and higher plant small subunits of ribulose bisphosphate carboxylase-oxygenase.the small subunits of spinach ribulosebisphosphate carboxylase-oxygenase were isolated by mild acid precipitation of the hexadecameric holoenzyme. about one-third of the small subunits remained in the supernatant while the remainder, and all of the large subunits, were precipitated and irreversibly denatured. the spinach small subunits were able to reassemble with the large subunit octamer of ribulosebisphosphate carboxylase-oxygenase from the cyanobacterium, synechococcus acmm 323, prepared as ...19853921534
chromatic adaptation in a mutant of fremyella diplosiphon incapable of phycoerythrin synthesis.a mutant of the chromatically adapting cyanobacterium fremyella diplosiphon, incapable of phycoerythrin synthesis but responding to wavelength modulation of its biliprotein content, was isolated. the biliprotein composition of the mutant and of the wild type were identical after growth in red light, but green light induced, in the mutant, the synthesis of a biliviolin-type chromophore bound to some of the alpha subunits of its phycocyanin. implications of the results on the regulation and possib ...19853922434
microinjected photoreactivating enzymes from anacystis and saccharomyces monomerize dimers in chromatin of human cells.photoreactivating enzymes (pre) from the yeast saccharomyces cerevisiae and the cyanobacterium anacystis nidulans have been injected into the cytoplasm of repair-proficient human fibroblasts in culture. after administration of photoreactivation light, pre-injected cells displayed a significantly lower level of uv-induced unscheduled dna synthesis (uds) than non-injected cells. this indicates that monomerization of the uv-induced pyrimidine dimers in the mammalian chromatin had occurred as a resu ...19853923332
effects of environmental factors on toxicity of a cyanobacterium (microcystis aeruginosa) under culture conditions.effects of light intensity, temperature, and nutrients on the toxicity of microcystis aeruginosa were investigated, using a toxic strain which kills mice. a marked change in toxicity was observed in the light intensity experiment, and slight changes were observed to be caused by temperature and phosphorus deficiency.19853923932
interaction effects of mercury-pesticide combinations towards a cyanobacterium. 19853924147
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